1. Field of the Invention
The present invention relates generally to systems for detecting obstacles and avoiding collisions. In particular, the present invention relates to an obstacle detection and collision avoidance system that uses audible alerts to warn a driver of an approaching obstacle.
2. Description of the Related Art
The Consumer Product Safety Commission estimates that each year about 110 people in the United States die while riding snowmobiles, and 13,400 others seek hospital treatment for injuries sustained in snowmobile accidents. Approximately two-fifths of snowmobile-related deaths occur when drivers collide with trees, wires, bridges, and especially other snowmobiles. There is a great need in the industry for a product to reduce the number of snowmobile accidents.
Snowmobile designers offer many safety features, including protective windshields, body and frame designs for protecting crash victims, improved braking systems, and emergency kill systems. However, little has been done in the area of collision avoidance systems suitable for use by snowmobiles and other off-road vehicles.
Vehicle guidance and collision detection systems have been developed for automobiles, as well as military defense systems, avionics systems, and space exploration systems. However, this technology is costly and has not been commercialized in a manner suitable for snowmobiles.
Several prior art patents disclose collision avoidance systems for use with automobiles. Among these systems are computer-controlled systems that process signals from various types of object sensors to determine a safe following distance for the host vehicle to avoid a collision. Other prior art systems include inputs from steering sensors to determine which obstructions are in the projected path of travel of the host vehicle. Still other systems use multiple sensors positioned around the vehicle and/or other inputs, such as GPS, to provide additional information for avoiding collisions. Examples of such prior art systems are briefly described below.
Kinoshita et al. (U.S. Pat. No. 6,114,951) disclose a vehicle collision preventing apparatus that uses an image processor and a computer for calculating inter-vehicle distance to observe and maintain a safe following distance behind another vehicle traveling in the same direction.
Yavnayi et al. (U.S. Pat. No. 5,388,048) disclose a vehicle anti-collision device that uses a laser range-finder mounted near the windshield of the host vehicle to determine the distance and closing velocity of a leading vehicle. A safe following distance is then calculated based on information from the laser range-finder and a determined self-speed of the host vehicle.
Gustafson (U.S. Pat. No. 6,014,601) discloses a driver alert system that uses a laser transmitter to transmit a laser beam at an object, and a laser receiver to receive a reflection of the laser beam. A processing unit calculates the relative speed of the object using information from the vehicle speedometer system, and also calculates a distance from the object and a relative acceleration of the object with respect to the vehicle. The system uses a linear light system to display the level of safety or danger.
Waffler et al. (U.S. Pat. No. 5,477,461) disclose a method for avoiding collisions of a motor vehicle with an obstacle that uses a plurality of scanning beams emitted fanwise in and beside the motion path of the vehicle. The output from the scanning beams is fed to an evaluation unit along with a steering angle signal to determine which obstacles pose a danger in the projected path of the vehicle.
O'Brien et al. (U.S. Pat. No. 5,341,344) disclose an obstacle-detection system in which a plurality of microwave-transceiver sensors are positioned around the vehicle. The signals reflected from objects around the vehicle are processed by a control unit, and an alarm is sounded if a detected object is determined to be a threat to the vehicle.
Abst et al. (U.S. Pat. No. 5,339,075) disclose a vehicular collision avoidance apparatus that uses an ultrasonic transmitter/receiver to detect when there is a threat of changing lanes into the path of another vehicle. The device is activated by the turn signal indicator control of the host vehicle and emits an audible warning signal with a frequency related to a degree of threat from the other vehicle.
Sindle (U.S. Pat. No. 5,173,881) discloses a vehicular proximity sensing system in which a plurality of ultrasonic distance-detector devices are disposed around a vehicle's periphery. A simulated vehicle display is provided on the dashboard to alert the diver to the close approach of an external object.
Lemelson et al. (U.S. Pat. No. 6,553,130) disclose a motor vehicle warning system that uses a TV camera mounted on the vehicle and an image processor to analyze the video images and identify obstacles. A warning means is used to warn the driver of approaching and existing hazards.
Ichikawa et al. (U.S. Pat. No. 6,408,247) disclose an obstacle detecting system that uses output from a radar device and information from wheel speed sensors and a yaw rate sensor to determine whether a detected obstacle is a collision threat.
Breed et al. (U.S. Pat. No. 6,405,132) disclose an accident avoidance system that uses GPS ranging signals to monitor the positions of vehicles and approaching dangers on a roadway. This system relies primarily on stored information of roadway lane and boundary locations and information received by GPS from other vehicles on the road to determine when dangers are approaching. Breed et al. also use a radar system and/or a laser radar for detecting vehicles and other hazards that are not equipped with a GPS transmitter.
The conventional collision avoidance systems described above are not suitable for use with snowmobiles and other off-road vehicles because they are generally too complicated, they fail to discriminate between obstacles that pose a real danger threat and obstacles that pose little or no danger, and/or they are not equipped with a suitable interface for alerting the driver of an approaching danger. Thus, there is a need in the industry for an improved collision avoidance system suitable for use with snowmobiles and other off-road vehicles.